Lauren Conrad knows that if it's not broke, don't fix it, as these waves have become her signature. And with good reason: "It's about angling layers out the right way—not boxing the face in. That'll make a round face look shorter," hairstylist Andy Lecompte says. Steal her look by asking your stylist for loose, face-framing layers, the first ones beginning slightly past the chin. Add waves by wrapping sections of the hair around a one-and-a-quarter-inch-barrel curling iron, feathering it away from the face. Brush through curls with a wire-bristle brush, like Sheila Stotts's Application Brush, he says. "You can back-comb and tease with the same brush for volume and shine."

"A heavy fringe is really flattering on Nicole," says Lecompte, who gave Richie this shaggy, shoulder-length cut. To prevent bangs from shortening a round face, adjust the width. Lecompte snipped these ones just above the eyelashes from cheekbone to cheekbone, angling them down at the sides about three quarters of an inch. "This really plays up her eyes," he says. He blew them dry with a round brush, smoothed them over with a flatiron, and dabbed on Wella Professionals Velvet Amplifier. "It's actually a primer, but I like to finish with it. It's matte, so it doesn't look greasy, and it brings stability to hair."

Adele's collarbone-grazing cut has a balancing effect: The fullest part of a round face is at the cheeks, so keeping the weight at the ends of strands enhances angles along the jawline. "This is about having almost one length, but a few soft layers at the bottom add thickness," Lecompte says. It has a gorgeous retro feel, but be wary of overstyling. Set hair with hot rollers, then brush through curls and let them take their own shape. "The imperfection is what makes it modern," he says.

Don't be afraid to go short. Ginnifer Goodwin's piecey fringe, paired with short, tapered sides, gives definition to her round face. Before your stylist picks up a pair of scissors, though, be sure to ask for softness around the ears. "Clipping too much will look masculine," Lecompte says. He also recommends styling with your fingers to avoid stiffness. "Using a brush or flatiron will give too much artificial shape."

A superlong cut like Penélope Cruz's lengthens the face, and subtle layers starting near her collarbone prevent it from falling flat. "Those light layers, achieved with thinning shears, give it a little lift, but it still looks like it's one length," he says. Long hair is prone to split ends, so maintenance is important: Treat it with a weekly mask, like Shu Uemura Art of Hair Moisture Velvet Nourishing Treatment for Dry Hair, and a bimonthly trim.

Don't be intimidated by the thought of bangs—they don't always accentuate a round face. Kirsten Dunst's sweeping fringe, which she matched with a deep side part and a shoulder-length cut, actually thins her face. "The longest bit of the bang hits midlip, but when you blow it dry and sweep it over, it grazes the cheekbones and defines them really nicely," Lecompte says. He suggests running a texturizer (we love Garnier Fructis Style Pure Clean Finishing Paste) over strands for control.